malloc() works

P-Gu · Apr 6, 2022 · e983d20 · e983d20
1 parent db9aff7
commit e983d20
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Showing 8 changed files with 21 additions and 40 deletions.
diff --git a/apps/app.lds b/apps/app.lds
@@ -42,6 +42,7 @@ SECTIONS
  .heap (NOLOAD) : ALIGN(8) {
  PROVIDE( __heap_start = . );
  . = __heap_size;
- PROVIDE( __heap_end = . );
  } >ram :ram
+
+ PROVIDE( __heap_end = 0x08008000 );
 }
diff --git a/earth/earth.c b/earth/earth.c
@@ -19,10 +19,11 @@ extern char data_rom_start, data_ram_start, data_ram_end;
 struct earth *earth = (void*)GRASS_STACK_TOP;
 
 int main() {
- memset(&bss_start, 0, &bss_end - &bss_start);
- int data_size = &data_ram_end - &data_ram_start;
- memcpy(&data_ram_start, &data_rom_start, data_size);
-
+ for (int i = 0; i < (&bss_end - &bss_start); i++)
+ ((char*)&bss_start)[i] = 0;
+ for (int i = 0; i < (&data_ram_end - &data_ram_start); i++)
+ ((char*)&data_ram_start)[i] = ((char*)&data_rom_start)[i];
+
  earth_init();
 
  INFO("Start to load the grass layer");

diff --git a/earth/earth.lds b/earth/earth.lds
@@ -4,7 +4,7 @@ ENTRY(_enter)
 
 MEMORY
 {
- ram (arw!xi) : ORIGIN = 0x08000000, LENGTH = 0x2000
+ ram (arw!xi) : ORIGIN = 0x08000000, LENGTH = 0x2800
  rom (irx!wa) : ORIGIN = 0x20400000, LENGTH = 0x400000
 }
 
@@ -18,7 +18,7 @@ PHDRS
 
 SECTIONS
 {
- __heap_size = 0x800;
+ __heap_size = 0x1000;
 
  /* ROM Sections */
  .init : {
@@ -52,9 +52,9 @@ SECTIONS
  .heap (NOLOAD) : ALIGN(8) {
  PROVIDE( __heap_start = . );
  . += __heap_size;
-  PROVIDE( __heap_end = . );
- } >ram :ram
- 
+ } >ram :ram 
+ PROVIDE( __heap_end = 0x08002800 );
+
  PROVIDE( bss_start = ADDR(.bss) );
  PROVIDE( bss_end = ADDR(.bss) + SIZEOF(.bss) );
  PROVIDE( data_rom_start = LOADADDR(.data) );

diff --git a/grass/grass.lds b/grass/grass.lds
@@ -42,6 +42,6 @@ SECTIONS
  .heap (NOLOAD) : ALIGN(8) {
  PROVIDE( __heap_start = . );
  . = __heap_size;
- PROVIDE( __heap_end = . );
  } >ram :ram
+ PROVIDE( __heap_end = 0x08005000 );
 }
diff --git a/library/egos.h b/library/egos.h
@@ -63,11 +63,3 @@ extern struct earth *earth;
 #define FATAL earth->tty_fatal
 #define SUCCESS earth->tty_success
 #define CRITICAL earth->tty_critical
-
-#undef malloc
-#define malloc my_alloc
-void* my_alloc(unsigned int size);
-
-#undef free
-#define free my_free
-void my_free(void* ptr);
diff --git a/library/file/file.c b/library/file/file.c
@@ -433,7 +433,7 @@ int treedisk_create(block_store_t *below, unsigned int below_ino, unsigned int n
  INFO("treedisk: Created a new filesystem with %d inodes\n", ninodes);
  }
  else {
- INFO("treedisk: Attempted to create a new filesystem, but one already exists with %lu inodes",
+ INFO("treedisk: A filesystem already exists with %lu inodes",
  superblock.superblock.n_inodeblocks * INODES_PER_BLOCK);
  }
 

diff --git a/library/libc/malloc.c b/library/libc/malloc.c
@@ -4,36 +4,23 @@
  */
 
 /* Author: Yunhao Zhang
- * Description: EGOS uses my_alloc() and my_free() instead of 
- * the malloc() and free() in metal-libc in order to reduce the
- * size of the code segment; This file is a naive implementation 
- * and a better one is left to students as an exercise.
+ * Description: system support to C library function malloc()
  */
 
 #include "egos.h"
 
-/* heap region is defined in the memory layout scripts */
 extern char __heap_start, __heap_end;
-static char* brk = &__heap_start;
-
+char* brk = &__heap_start;
 
 char *_sbrk(int size) {
- if (brk + size >= &__heap_end) return (void*)-1;
+ if ((brk + size) > (&__heap_end)) {
+ earth->tty_write("_sbrk: heap is full\r\n", 21);
+ while(1);
+ }
 
  char *old_brk = brk;
  brk += size;
  for (int i = 0; i < size; i++) old_brk[i] = 0;
 
  return old_brk;
 }
-
-
-void* my_alloc(unsigned int size) {
- if (brk + size >= &__heap_end) FATAL("Heap is full");
-
- char* old_brk = brk;
- brk += size;
- return old_brk;
-}
-
-void my_free(void* ptr) {}
diff --git a/library/libc/print.c b/library/libc/print.c
@@ -4,7 +4,7 @@
  */
 
 /* Author: Yunhao Zhang
- * Description: system support to C library functions such as printf
+ * Description: system support to C library functions like printf()
  */
 
 #include "egos.h"